How can the voting app on dabgo.com recognize me across browsers?

Question

I noticed that once I cast my vote in this app (dabgo.com) in my standard browser (Chrome), I cannot cast another vote by using FireFox, Opera or Safari (nor using incognito mode).

How is that done?

Answer 1

Interesting question. There are ways around this if you want to cast multiple votes (like I did). Your browser needs to 'forget' that it visited that site, and remove all traces. There are some holes you can exploit. You do this with a quite weird set of steps - like this:

1. Install the AVG extension on Chrome: https://chrome.google.com/webstore/detail/avg-web-tuneup/chfdnecihphmhljaaejmgoiahnihplgn
2. Go to the dabgo.com website in Chrome, and open 28 tabs (no more, no less - if you open too many, start over).
3. Go to the dabgo.com website in all tabs - starting with the last one and then moving backwards (do not skip any, - start over if you do)
4. In tab number 7, hold shift and F5, so it refreshes. Repeat 7 times.
5. Now you can vote as many times as you want, in that same tab.

I told you it was weird steps! What you are doing is encapsulating the request and thereby also the cookies created, and with those exact tab numbers, the probability of hitting the same cookie is almost zero.

Let me know if you have problems. There are other ways - this is the simpler one.

Answer 2

It could be as simple as allowing only one vote per IP address, or more complex like device fingerprinting where the server is using a combination of signals about your device (IP address, screen resolution, GPU, network latency, etc, etc, etc) and using some probability threshold to correlate separate visits as likely to be from the same user. There's no way to know for sure without access to their anti-fraud algorithm, but you could test against some of those assumptions. You could also try Tor or a VPN or proxy, but they may have defenses against those too.

You may want to contemplate the ethics of voting more than once.